Double-blind comparison of the efficacy and safety of single doses of meptazinol as a suppository and morphine by i.m. injection.

The analgesic efficacy of a 150-mg meptazinol suppository was compared with that of morphine 10 mg i.m. in the treatment of moderate postoperative pain. Two groups of 15 female patients took part in a 4-h, randomized double-blind, double-dummy study on the first day after elective abdominal hysterectomy. Meptazinol did not provide satisfactory analgesia in five patients (P less than 0.05). A decrease in mean pain scores (linear analogue scale and verbal rating scale) was seen after the administration of meptazinol, but this was not as great as that produced by morphine i.m., nor was it as long in duration. Significant changes in arterial pressure, heart rate and ventilatory rates were not seen in association with the administration of meptazinol, but were observed after the administration of morphine.